Paris — British lawmakers have debated banning his entry to their country. A former Australian prime minister said the prospect of his presidency made him “tremble.” Piñatas in his image, complete with his signature coif, have become all the rage in Mexico.

The unorthodox march of Donald Trump toward the Republican nomination has transfixed audiences from London to Latin America. The world has looked on with confusion, consternation, and a few congratulations at the prospect that a brash billionaire with no political experience, who says whatever he wants, could possibly find his way to the White House.

Any US presidential race is hot-ticket international news. But this one comes at a time of deep global insecurity. Mr. Trump’s status as an unknown quantity feeds nations’ worries about everything from the continuation of their trade deals to military ties.

Yet the rise of Trump is also seen in many corners as a gauge of Americans’ concerns about their diminishing role on the world stage. In Europe, this is something of a familiar phenomenon as populists gain at the polls, fueled by frustration over migration, globalization, and social change.

If there is an optimistic side, it lies in the hope of many that, whether he wins or not, Trump’s candidacy will have jostled political elites and forced them to address the gap between a widespread sense of malaise and the simplistic, often outrageous solutions of straight-talking populists.

“It is quite clear that people are not happy with the establishment, and they are so unhappy that they are willing to overlook some pretty serious xenophobia,” says Christine Harlen, who teaches US politics and international political economy at the University of Leeds in England. “Maybe it could be a wake-up call that something has to change.”

Like that of other populists gaining footholds around the world, Trump’s rise is seen as first and foremost a protest.

While Trump’s plans to build a wall along the US-Mexican border and make Mexico pay for it, or temporarily bar Muslims from visiting the United States – which prompted the extraordinary debate in Britain’s Parliament – have attracted a fair share of racist voters, his appeal ripples wider. His supporters like his style as the anti-politician: muscular and even vulgar in speech, deriding the political dysfunction in Washington that has allowed everyday problems to mount.

‘A new face and a new force.’

As Zhu Feng, an analyst of South China Sea issues at China’s Nanjing University, puts it: “He is a real American. I do not see Trump as below the standards of American politics. He is a new face and a new force, and he carries a lot of the real hopes of American people.”

The desire for change is apparent to US neighbors north and south, from the industrial hubs in Canada to the towns along the US-Mexican border. “Americans are overall just angry in a lot of ways,” says Brian Hogan, who works in Windsor, Ontario, across the river from Detroit. “There’s a lot of rancor in that country.”

Mr. Hogan says his American friends feel unstable in their jobs and shaken by racially charged violence and gun crime.

“When people have personal challenges they look for answers,” says Hogan, who leads a local teachers union. “If someone is a racist but he’s going to get you a job, you’d be interested.”

But this is more than just a story of disillusioned individuals. To America’s allies, Trump’s appeal is also an expression of a nation that can’t find its way amid new geopolitical currents, from the rise of China to that of the so-called Islamic State to the country’s own isolationist mood.

Clive Hamilton, a professor of public ethics at Charles Sturt University in Canberra, Australia, says a substantial number of Americans are accommodating the US’s changing place in the world instead of resisting it. But others are angry and resentful about America’s inability to sway the Syria conflict, for example, or what they see as disruptive changes at home, such as the legalization of gay marriage, and a conviction that they aren’t making headway in a system skewed against them.

Trump’s backers, Mr. Hamilton says, feel vulnerable to invasion: “I’m not talking of military invasion. I’m talking of invasion by economic powers, by financial powers, by immigrants coming up from the south and across the seas – a generalized sense of insecurity that’s taken root in the American populace, which is at the heart of the Trump phenomenon.”

In Asia, this can seem like déjà vu. In Tokyo, Trump’s angry words toward Japan have revived memories of the 1980s trade tensions with the US, provoking puzzlement among those who have witnessed Japan’s struggle with economic stagnation and being overtaken by China in the intervening decades.

Trump has also questioned the validity of the US-Japan security alliance, the bedrock of relations between the two countries since World War II. He accuses Tokyo of not paying enough for the protection it receives from the US. “If Japan gets attacked, we have to immediately go to their aid,... if we get attacked, Japan doesn’t have to help us. That’s a fair deal?” Trump asked at a rally in Iowa last August.

Many in the world understand his rise through their own country’s political experiences. That includes similar public figures who have made headlines, from former Italian Prime Minister Silvio Berlusconi to businessman Kevin O’Leary in Canada to former Osaka Mayor Toru Hashimoto in Japan. But it also touches on populism and a desire for a strong, independent – and rich – leader. This has been a feature of public life in Latin America for decades.

Independent, wealthy leaders attractive

“Urbanization, industrialization brought modernization that challenged traditional norms, and that made people feel scared about their position in society,” says Christopher Sabatini, an associate professor at Columbia University’s School of International and Public Affairs in New York. In the Latin American context, independently wealthy leaders always get a second look from voters who feel they’ll be less prone to corruption by businesses or drug traffickers.

In today’s world, insecurity is fueling what might be described as the global appeal of the “strongman.” Motti Chaimovitz, a Tel Aviv cafe owner, says he has to look no further than home to understand Trump’s gains: It’s like the dynamic that swept Prime Minister Benjamin Netanyahu into office.

“There is a prevailing fear in the Western world. People are looking for strong candidates,” he says. “Those that put [Turkish President Recep Tayyip] Erdoğan and Netanyahu in power are the religious and rural vote.”

Perhaps the most apt comparisons today, however, come from Europe, where populists are gaining from France to Finland – putting some European leaders on the defensive. European-American relations were strained under former President George W. Bush, but the prospect of a Trump presidency has been viewed with a degree of panic.

Germany’s influential weekly magazine Der Spiegel wrote in a Jan. 2 headline that “Donald Trump Is the World’s Most Dangerous Man,” and elaborated in the subhead. “George W. Bush’s America,” it reads, “would seem like a place of logic and reason in comparison.” And The Economist Intelligence Unit ranked a Trump presidency as one of the top 10 risks facing the world, on a par with jihadi terrorism and more threatening than a military conflict in the South China Sea.

The mainstream parties have been faulted for underestimating the appeal of populism. Steven Ekovich, a professor of comparative politics at The American University of Paris, says they continue to denigrate populist supporters instead of looking in the mirror.

“One similarity between the US and France is the French elite have been disdainful and mocking of anyone supporting Marine Le Pen,” he says. “They are essentially verbally spitting on them, which has only reinforced Marine Le Pen’s support.”

Tapping populism

Some of Europe’s populists have publicly supported Trump. Russian President Vladimir Putin has called him “brilliant” – after Trump said he believes he could get along with the Russian leader. From Moscow’s vantage point, such leaders taking hold of Western public imagination is no surprise.

“I think Trump is the product of the same kind of ferment we see happening in Europe. People are disillusioned with the status quo and the standard answers issued by old-line politicians, and they want change,” says Andrei Klimov a member of the Federation Council, Russia’s upper house of parliament. “He obviously appeals to a lot of people out there, who maybe say, ‘I don’t know where Ukraine is. I don’t understand what we’re doing in Syria. I don’t want to feed refugees. Why can’t we just look after our own?’ ”

While many voters may identify with this sentiment analysts warn that the promises of populism are too simplistic.

Mark Triffitt, a lecturer in public policy at the University of Melbourne in Australia, argues that the insecurity people feel “lends itself to a mind-set that America should retreat and go back to a world which is very difficult to reconstruct, one that is built around a dominant manufacturing sector, one centered on an unambiguous sense of American power.”

No one is predicting the shape that US foreign policy would take under Trump – mostly because he is unpredictable, either not detailing his positions or changing them rapidly. But many are already worried.

Iranians, for example, are eager to know if the landmark nuclear deal painstakingly negotiated for years and finally agreed to last July between Iran and six world powers will be “torn up,” as some Republican candidates have promised.

Kayhan Barzegar, director of the Institute for Middle East Strategic Studies in Tehran, Iran, says Trump could endanger US interests “considering the reality that US power ... requires engaging others [in] solving the world’s common problems.”

Daniel Friedrich, a teacher in Berlin, has faith that if Trump is elected the American democracy would restrict him so that the world order would remain much as it is now.

“In the end, no matter who the president is, the president is constrained in all kinds of ways by other institutional factors,” he says, “so I think that the effect might not be as bad as one might think at first sight, just as the effect of [President] Obama was not as good as one might have hoped for.”

But Josefina Ponce, a waitress and college student of psychology in Mexico City, says Trump is changing her view of the US.

“I have gone from feeling ‘he doesn’t represent all Americans’ to feeling like ‘maybe I don’t understand the US like I thought [I did],’ ” she says.

US global leadership could suffer a similar image problem, which, according to Andreas Schwab, a German member of the European Parliament, would have untold consequences for mutual trust. He goes so far as to say a Trump victory would be “a big blow to the unity of the Western world.

“In comparison to other world powers, this has always been the US’s biggest strength: keeping like-minded countries together with a very soft approach, linking them one to the other. I do not think that it would be the same with Trump,” he says.